Synthesis 2018; 50(07): 1511-1520
DOI: 10.1055/s-0036-1591737
© Georg Thieme Verlag Stuttgart · New York

Intramolecular Cycloaddition Approach to Fused Pyrazoles: Access to 4,5-Dihydro-2H-pyrazolo[4,3-c]quinolines, 2,8-Dihydroindeno[2,1-c]pyrazoles, and 4,5-Dihydro-2H-benzo[e]indazoles

Moumita Jash
Organic & Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata-700032, India   Email: [email protected]
Bimolendu Das
Organic & Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata-700032, India   Email: [email protected]
Suparna Sen
Organic & Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata-700032, India   Email: [email protected]
Chinmay Chowdhury*
Organic & Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata-700032, India   Email: [email protected]
› Author Affiliations
M.J. thanks UGC, New Delhi for a fellowship. Partial Financial support from WB-DBT (GAP 340) is gratefully acknowledged.
Further Information

Publication History

Received: 26 September 2017

Accepted after revision: 10 November 2017

Publication Date:
12 December 2017 (online)


A straightforward and efficient method for the synthesis of pyrazoles fused with 1,2,3,4-tetrahydroquinoline, 2,3-dihydro-1H-indene­, or 1,2,3,4-tetrahydronaphthalene involves the formation of the tosylhydrazone from an aromatic substrate carrying aldehyde and acetylenic functionalities at appropriate positions, followed by base-promoted generation of the diazo compound and subsequent intramolecular 1,3-dipolar cycloaddition. A number of functional groups were found to be compatible for this reaction sequence and yields were moderate to very good (44–95%). A plausible reaction mechanism supported by DFT calculations has been provided to explain the formation of products.

Supporting Information

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